Is there a Better Option than Metronidazole for C. Diff?
Vancomycin may be a more effective treatment for severe clostridium difficile infection (CDI) than metronidazole, according to a study published in the Journal of the American Medical Association (JAMA. Published online ahead of print February 6, 2017. doi:10.1001/jamainternmed.2016.9045).
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Metronidazole hydrochloride has historically been used as a first-line treatment for patients with mild to severe CDI despite its inferiority to vancomycin. The choice of which therapy to use undoubtedly has consequences on downstream outcomes, such as recurrence and mortality, which have not been studied as much as mainline outcomes
Therefore, researchers led by Vanessa W Stevens, PhD, IDEAS 2.0 Center, Veterans Affairs (VA) Salt Lake City Health Care System, (Salt Lake City, UT) conducted a study aimed at improving the existing evidence on recurrence and all-cause 30-day morality among patients receiving metronidazole or vancomycin.
For the study, researchers performed a retrospective, propensity-matched cohort study of patients treated for CDI in the VA Healthcare System from January 2005 through December 31, 2012. Eligible patients were those with CDI as measured by the Centers for Disease Control and Prevention laboratory definition, which is based on a the presence of C difficile toxin or toxin gene in stool samples. Patients were excluded if they did not receive either metronidazole or oral vancomycin, or if they received both medications within 2 days before or after CDI diagnosis.
A total of 47,47 patients developed CDI and were treated with vancomycin or metronidazole during the study period and included in the final analysis. Of those 47,471 patients with first eligible treatment episodes, 2068 (4.4%) received vancomycin as initial therapy. Vancomycin was used among 1112 patients (4.4%) with mild to moderate CDI, 630 (3.6%) with severe CDI, and 326 (6.8%) with CDI of unknown severity. Those 2068 patients were matched to 8069 patients in the metronidazole group for a total of 10,137 included patients.
Overall, there were no differences in risk of recurrence in those treated with vancomycin versus those treated with metronidazole regardless of disease severity cohorts. However, patients treated with vancomycin were significantly less likely to die compared with metronidazole users. Patients with severe disease who received vancomycin also had a reduced risk of all-cause 30-day mortality.
"For many years the two antibiotics were considered to be equivalent in their ability to cure C. diff and prevent recurrent disease," Dr Stevens said in a press statement released along side the study (University of Utah press release. Published February 6, 2017; Salt Lake City, UT). "Our work and several other studies show that this isn't always the case."
Researchers concluded that while recurrence rates may be similar among patients treated with vancomycin and metronidazole for CDI, the risk of 30-day mortality can be significantly reduced with vancomycin.—Sean McGuire
